Ritual Activity
It is usually observed for 12 days, and during that time the devotee subsists on a diet of milk alone. [1]
In Hindu Mythology
A notable event is that of Sage Kashyap who asked his wife, Aditi, to use this method to please Lord Narayana so that a solution could be found for her son who was defeated by the Asuras. This penance finally resulted in the Vamana Avatar sending Mahabali to the netherworld. [2]
References
Payovrata Wikipedia(Text) CC BY-SA